A universal joint, as well known in the art, is simply a device for connecting two objects, as the ends of two shafts, so as to allow the objects perfect freedom of motion in every direction within certain defined limits. The principal purposes of a universal joint when used to connect two ends of a drive shaft for a vehicle is to allow the shaft to flex when the axle of the vehicle is moving. The universal joint absorbs the torsional shock and angular movement of the drive shaft when the vehicle travels over uneven terrain allowing the vehicle suspension to move up and down and unevenly on its springs. It is well known in the art that in agricultural and construction type vehicles the universal joint is subjected to an extraordinary amount of vibrations and stresses resulting in a substantial amount of wearing of the elements of a universal joint to the end that breakdowns are common, frequent and costly in that type of vehicle.
When excessive vibration occurs in a vehicle because of a breakdown or wearing of one or more elements of the universal joints of the art, there are few repairs that can be made at the site of the breakdown beyond, for example, tightening the flange bolts connecting the ends of the drive shafts to the joint, in the hope that such remedy will cure the vibration. In most instances of known universal joints, no repair of, or to, a universal joint can be made without removing the joint. It will be appreciated by those skilled in the art that when it is necessary to remove a universal joint from operative engagement for repair, the vehicle must be taken out of service, consequently shutting down the operation. The vehicle must be taken to a garage having the proper tools and lifts for the difficult job of removal. None of the universal joints of the art permit either easy field repair, or means to readily and effectively compensate for field repair. Exemplary of universal joints known in the art and to which the present invention represents an improvement are U.S. Pat. Nos. 714,327; 1,106,325; 2,903,868; 3,310,959; and 3,486,349; British Pat. Nos. 18,689 (1914) and 1,126,110; and German Pat. No. 719,856 (1942).